We examine whether exposure to direct-to-consumer advertising (DTCA) for antidepressant drugs affects individual use of these medications among those suffering from depression. Prior studies have almost exclusively relied on making connections between national or market-level advertising volume/expenditures and national or individual-level usage of medications. This is the first study to: estimate the impact of individual-level exposure to DTCA on individual-level use of antidepressants; estimate the impact of individual-level exposure to television DTCA on individual-level use in any drug class; consider the relative and interactive impact of DTCA in two different media in any drug class; and, consider the heterogeneity of impact among different populations in an econometric framework in the antidepressant market. There are also important limitations to note. Unlike prior market level studies that use monthly data, we are limited to aggregated annual data. Our measures of potential advertising exposure are constructed assuming that media consumption patterns are stable during the year. We are also not able to study the impact of advertising on use of antidepressants for conditions other than depression, such as anxiety disorders. We find that: DTCA impacts antidepressant use in a statistically and economically significant manner; that these effects are present in both television and magazine advertising exposure but do not appear to have interactive effects; are stronger for women than for men in the magazine medium, but are about equally strong for men and women in the TV medium; and, are somewhat stronger for groups suffering from more severe forms of depression. The overall size of the effect is a 6-10 percentage point increase in antidepressant use from being exposed to television advertising; the corresponding magazine effects are between 3 and 4 percentage points.
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